The present invention relates to a locking mechanism for a planing block with blades of a planing machine.
A conventional planing machine has a locking mechanism for locking the planing block to fasilitate replacing and positioning plane blades on the planing block and to ensure safety during the replacement or positioning work.
Such a conventional locking mechanism employs a structure disclosed in Utility Model Publication No. 62-41768. This mechanism comprises a number of grooves formed on the axis of a planing block, and a locking lever having a locking piece to be detachably engbaged with one of the grooves, which is rotatably fitting on a frame supporting the planing block. The locking lever is constatly urged by a spring towards the direction to lock the locking piece in a groove. In order to keep the locking piece away from the grooves against the urging force of the spring, the locking lever has a hole into which a stopping pin on the frame is inserted. Therefore, when the blades are replaced, the locking lever is bent to take out the stopping pin from the hole and then the locking lever is rotated so that the locking piece is inserted in a groove for the replacement of the blades. In this way, the planing block is locked and replacement of plane blades is conducted. For adjusting position of plane blocks, the stopping pin is taken out of the hole in the locking lever to cause the locking lever to rotate so that the locking piece is held in a groove for the positioning, which locks the planing block and the positioning work is conducted. When the replacement or positioning is completed, the planing block is unlocked by inserting the stopping pin into the hole in the locking lever.
However, the above conventional mechanism requires that the planing block is kept unlocked by inserting the stopping pin into the hole in the locking lever, when no replacement or positioning of plane blocks is conducted. In other words, the locking/unlocking of the planing block is not interlocked with opening/closing of a cover for the planing block. Therefore, the cover has to be opened to expose the planing block before pulling out the stopping pin from the hole in the locking lever to lock the planing block.